1. The Field of the Invention
The present invention relates generally to optical transmitters and receivers. More specifically, the present invention relates to optical transmitters and receivers that use microcode and/or tables to trigger alerts based on dynamic digital diagnostics.
2. The Relevant Technology
Computing and networking technology have transformed our world. As the amount of information communicated over networks has increased, high speed transmission has become ever more critical. Many high speed data transmission networks rely on optical transceivers and similar devices for facilitating transmission and reception of digital data embodied in the form of optical signals over optical fibers. Optical networks are thus found in a wide variety of high speed applications ranging from as modest as a small Local Area Network (LAN) to as grandiose as the backbone of the Internet.
Typically, data transmission in such networks is implemented by way of an optical transmitter (also referred to as an electro-optic transducer), such as a laser or Light Emitting Diode (LED). The electro-optic transducer emits light when current is passed through it, the intensity of the emitted light being a function of the current magnitude. Data reception is generally implemented by way of an optical receiver (also referred to as an optoelectronic transducer), an example of which is a photodiode. The optoelectronic transducer receives light and generates a current, the magnitude of the generated current being a function of the intensity of the received light.
Various other components are also employed by the optical transceiver to aid in the control of the optical transmit and receive components, as well as the processing of various data and other signals. For example, such optical transceivers typically include a driver (e.g., referred to as a “laser driver” when used to drive a laser signal) configured to control the operation of the optical transmitter in response to various control inputs. The optical transceiver also generally includes an amplifier (e.g., often referred to as a “post-amplifier”) configured to amplify the channel-attenuated received signal prior to further processing. A controller circuit (hereinafter referred to as the “controller”) controls the operation of the laser driver and post-amplifier.
The operation of an optical transceiver is susceptible to its operating environment and degradation effects caused by aging. For example, laser driver current for a transmitter may be varied with operating temperature in order to maintain a particular optical transmit power at the beginning of life of the transmitter. As the transmitter ages, the laser driver current can be increased relative to the beginning of life to compensate for degraded performance. Eventually, however, the increased laser driver current reaches and/or exceeds an indicator value that is indicative of potentially imminent transmitter failure. Because the laser driver current varies with temperature, the indicator value for laser driver current also varies with temperature and is not a constant.
It is often desirable for users of optical transceivers to receive alerts when laser driver current reaches and/or exceeds the indicator value. This enables optical transceivers within a system to be replaced before the transceivers actually fail and at a convenient time for the users, such as at night when disruptions to the system's operations may have the least impact. Conventionally, a static value corresponding to a worst case scenario is chosen as the indicator value. It is only after the laser driver current reaches and/or exceeds the static indicator value that an alert is triggered, regardless of the operating temperature. The result is that many times an alert is not triggered even though the laser driver current exceeds the indicator value corresponding to the operating temperature due to the fact that the laser driver current has not exceeded the static indicator value. Clearly, the conventional solution for triggering alerts using a static value fails to account for dynamic operating and/or environmental parameters, such as dynamic operating temperatures.
What is needed, therefore, are improved methods and systems for triggering alerts in optical transceivers based on dynamic conditions.